It’s almost impossible to undersell the importance of Alien, both as a film in general and as a contribution to both science fiction and horror. It introduced mainstream audiences to Ridley Scott, one of the greatest directors of the last forty years. It proved that science fiction filmmaking could still be rooted in ideas and metaphors at a time when the likes of Star Wars were shifting the genre towards pure entertainment. And it scared the living daylights out of a generation of filmgoers, something which it still does more than thirty years on.Just as Blade Runner was both futuristic and nostalgic, drawing on and updating the conventions of film noir, so Alien is on one level a harmony between two separate schools of horror. On the one hand, it is a haunted house movie, based on a premise which stretches back to the 1920s: a building harbours an evil presence or creature, which bears ill will to the people inside. On the other hand, it draws on the slasher genre pioneered by Black Christmas and Hallowe’en, in which a group of people are picked off one by one by an evil force, who then meets its match in the shape of the ‘final girl’ as an avenging angel.

What Alien manages in one full swoop is to solve the central problem of both these genres by a combination of setting and character development. The flaw in most haunted house films is simple: if being in the house is so terrible, why not just leave? In Alien, there is no escape. The Nostromo is a never-ending labyrinth of corridors and air ducts, and a monster could be lurking behind any corner. The film is unbearably claustrophobic, to the point at which you find yourself feverishly scanning every corner of the screen as the panic steadily builds.Likewise, the flaw with most slashers is that the characters are so paper-thin that we don’t care about them. The main reason people paid to see all the Hallowe’en sequels and knock-offs was the elaborate and increasingly goofy manner in which the victims were killed. Somehow we went from Hallowe’en, with Michael Myers as the essence of evil and barely any gore on screen, to Lucio Fulci’s The New York Ripper, in which our antagonist stabs prostitutes whilst doing duck impressions.

Alien, on the other hand, takes its time to build up its characters in the opening act. The first hour is dreamlike and takes its time, from the slow Kubrickian shots of the corridors, to the time-lapse of John Hurt emerging from hyper-sleep, to the wry discussions about the poor quality food and the bonus situation. Even after the face-hugger attacks Kane, the film sticks to its guns and keeps the character development going. It builds up Brett and Parker’s outsider status and the lack of respect for Ripley, factors which become of key importance as the story unfolds.Alien has been described as the anti-2001, the blue-collar depiction of space against the gleaming white dignity of Kubrick’s vision. This is unsurprising, since its writer Dan O’Bannon also wrote and starred in Dark Star, John Carpenter’s oddball sci-fi comedy which contains many similar elements (albeit played for laughs). The Nostromo is a grimy and dingy place, inhabited by worldly-worn men and women who care about little more than getting paid and getting home. The elements of corporate paranoia and gender inequality which begin to infiltrate make Alien a compelling social commentary. ‘The company’, with Ash as its representative, is aloof, greedy and uninterested in the lives of ordinary people, or women in particular. These same ordinary people (and women in particular) end up saving the universe, albeit through massive and involuntary personal sacrifice.The acid test of all horror movies (no pun intended) is whether or not they remain scary, and Alien is still one of the scariest ever made. A large part of this lies in the technical construction of the film. Scott understands that true fear lies in the mind of the audience; people are not scared by what they see, they are scared by what they think they have seen. By showing so little of the alien until the very end, Scott plants a seed of fear and paranoia into the audience’s mind, which grows exponentially as the body count rises. The combination of lighting, camera angles and Jerry Goldsmith’s nail-biting score creates an atmosphere of unstoppable terror in which all one can do is watch, pray and scream.

Alien plays on the ancient fear of the unknown, challenging the audience’s curiosity and confounding our expectations. The most famous example of this is the ‘chest-burster’ or ‘birth’ scene, which is rightly considered one of the scariest scenes in cinema. In the scenes leading up to it, we are led to believe that the worst is over; the face-hugger is dead, Kane has come out of his coma, the ship has been repaired and they are once again on their way home. Then Kane starts to choke, something which is distressing but nothing out of the ordinary. Hence when the alien bursts through his chest, covering Lambert in blood, we sit there petrified at the sight of this creature and stunned by just how well we have been deceived.But it is not just the fear of the unknown which makes Alien so terrifying. The film draws on a long line of science fiction films which have dealt with some form of alien possession or violation of the human body. Mario Bava’s Planet of the Vampires is the most frequently cited influence, but there are also hints of Invasion of the Body-Snatchers and The Thing from Another World (which would later be remade as The Thing by John Carpenter). So much of horror is rooted in the idea of people we think we know turning out to be something else – vampires, pod people, mothers of xenomorphs, these are all means of challenging our perceptions of human identity.But Alien goes further than basic possession, equating the alien with the fear of rape or the male fear of pregnancy. H. R. Giger’s designs are insanely phallic – the long, curved head of the alien with its internal set of teeth, which extend like a thrusting phallus to violently penetrate and impregnate the victims. All the men on board are picked off before the women, and in the Director’s Cut we see chilling shots of their bodies being cocooned to serve as incubators for further aliens. Just as the Eraserhead baby is a metaphor for the father’s fears and dark secrets, so the alien is like a son that turns on its surrogate fathers.

There has been a great deal of discussion as to the feminist implications of the Alien franchise, with James Cameron’s instalment being held up as the greatest expression of this. But actually Alien has as good a case, if not a better one, because of the precise nature of Ripley’s transformation. Ripley spends much of the first film in a passive role – she is something of a goody-two-shoes, who goes by the book and has little respect from the lower orders of the crew. After the death of Dallas she becomes the leader or matriarch, but doesn’t take on traditionally male characteristics in doing so. While Parker goes into a battle-crazed rage, she remains calm and considered. She retains her maternal or feminine qualities, as shown by her decision to take Jones with her, and her defeat of the alien is a profound expression of her individual identity and refusal to be exploited. Compare that to Aliens, in which Ripley takes on much more macho or masculine qualities, undergoing a similar shift to Sarah Connor in Terminator 2.Alien remains a masterpiece of both science fiction and gothic horror, conveying deep psychological themes while scaring us to death. For all the talents of James Cameron and David Fincher (whose instalment is very underrated), it also remains the most complete and profound member of the franchise, a status which doesn’t look like being threatened any time soon. Sigourney Weaver is the stand-out from a note-perfect cast, and Ridley Scott’s direction is simply extraordinary, taking something utterly fantastical and making it terrifying real. A magnificent achievement from every angle, and the first of Scott’s many masterpieces.